Terra Branford, named Tina in the Japanese version, is a playable character in Final Fantasy VI. A half-human, half-Esper, Terra is one of the only humans able to naturally cast magic, Celes being only infused with the ability, and the only human-Esper hybrid in existence. Her unique abilities make her a key player in the war between the Gestahlian Empire and the rebel factions. Terra is depicted in-game with mint green hair, but in all other appearances, she has blonde hair.Her gameplay name before the player is able to name her is ??????, and her "name" in dialogue is Girl.

Yoshinori Kitase has stated in an interview that Final Fantasy VI has no official main character, as the developers aimed to give the entire cast equal development and standing without anyone standing above the rest. However, Terra features prominently in much of the game's artwork and is pivotal to its plot: she is present in the game's logo, the game's main theme is named after her and she was chosen as the heroine to represent Final Fantasy VI in Dissidia. Thus, she is widely considered to be the game's central protagonist among fans.

From the Final Fantasy Wiki article: http://finalfantasy.wikia.com/wiki/Terra_Branford